super Heaters

This topic has 16 replies, 9 voices, and was last updated 9 November 2015 at 22:39 by julian atkins.

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28 October 2015 at 16:58 #209610
Ron Hancock
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@ronhancock63652
Hi all well i would like some views from any one who knows about super heaters.

I went to my club today and got onto the subject of super heaters.

Several thought their was no gain for a 5" inch Loco with Cast iron cylinders.

They said that the wet steam once warm was negligible.

I thought it would loose steam hard to see in winter through the wet steam and would not steam as well as ones with super heaters.

Would love to hear your views as soon have to make my mind up witch way to go.

I had started to make they using stainless pipe over the fire going into copper.

Several thought they are more trouble than they are worth.

welcome some feedback.

My Loco is a Black 5 in 5"

Many Thanks

Ron
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28 October 2015 at 16:58 #1467
Ron Hancock
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@ronhancock63652
28 October 2015 at 19:31 #209635
Simon Collier
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@simoncollier74340
All the serious and prolific builders I know, and know of, use superheating.
28 October 2015 at 20:02 #209637
John Baguley
Participant
@johnbaguley78655
Hi Ron,

I am a big fan of superheat, the higher the better, and woudn't build a loco without it. It does make a big difference to the performance of the loco despite what the negative people will tell you. Less water and coal used and much livelier performance. With an unsuperheated version you get a shower every time you run, especially in cold weather, and you can't see where you are going half the time. Fully radiant versions that extend over the fire are far more effective than ones that just sit in the flues. They just dry the steam a bit but don't increase it's temperature very much. Go for it! Superheaters are not difficult to make. Forget the coax type though. Doug Hewson did some tests that showed they were pretty useless compared to the proper hairpin type.

John
28 October 2015 at 20:07 #209640
Neil Wyatt
Moderator
@neilwyatt
Never understood the coaxial design – the incoming steam is ideally placed to cool the outgoing steam.

Neil
28 October 2015 at 20:16 #209644
Ron Hancock
Participant
@ronhancock63652
thaHi John I have always been in the same mind.

I have already made an hairpin type with stainlell tips.

I was surprised when some members made the suggestion.

They seem to think superheater just causes more problems.

At the moment i can't see why I would not have one but as I have only been doing this for two years.

I thought I would wait and see what others thought in case my thinking is wrong.

Thank you John

Ron
28 October 2015 at 20:20 #209646
John Baguley
Participant
@johnbaguley78655
Neil,

I suspect that is the problem with the coaxial design. The incoming cooler steam must cool the outgoing hotter steam so any heat gain is cancelled out. I think the reasoning behind the design was that they are supposed to be easier to make as you don't need the fiddly return bend on the firebox end.

John
29 October 2015 at 18:57 #209754
Howard Lewis
Participant
@howardlewis46836
If superheating did not bring benefits, full scale marine, and loco engineers would never have gone to the trouble.

Go for it!

Howard
29 October 2015 at 19:39 #209758
Bob Brown 1
Participant
@bobbrown1
A superheater will add more energy for the same volume of steam which adds to the overall efficiency of a steam plant. It also means the steam is more of a gas with no water droplets entrained in it, mind you in full scale plant at the pressures and temperatures they run at a leak can cut steel. On model engines there are still benefits to be had even allowing for the added work in the tight space of the smoke box.

Bob
29 October 2015 at 21:27 #209793
Another JohnS
Participant
@anotherjohns
Posted by Howard Lewis on 29/10/2015 18:57:39:

If superheating did not bring benefits, full scale marine, and loco engineers would never have gone to the trouble.

Sometimes they didn't. The old Shay locomotive that I used to supervise steaming on was saturated steam, as was the old coal-fired steam crane, and countless other non-mainline full size locomotives.

Superheaters for models are a religious war; back in 2007 DAG Brown wrote an article "Superheating – is it really helpful?" which I'm sure was not taken politely by certain parties!

Me? Currently my model locomotive stable is superheaterless (or, to be exact, *one* has LBSC-style superheaters but the flue is completely blocked with ash) and they run more than fine, thank you! But, if you want that last bit of thermal efficiency, go for it.
29 October 2015 at 22:32 #209803
Ron Hancock
Participant
@ronhancock63652
I had ,made is so going to fit it.

might as well after making it and if i get problems then may rethink thank you guys

Ron
29 October 2015 at 23:06 #209810
julian atkins
Participant
@julianatkins58923
when you have run hour after hour all day long passenger hauling on a 5"g superheater fitted loco burning half the coal and putting on the injectors only half the time compared to a non-superheated loco, plus learnt how responsive and lively the loco is and responds to 'notching up' with a good valve gear, and your glasses dont get misted up when going through tunnels, the facts speak for themselves!

i agree 100% with John Baguley and Neil re his comments on the co-axial type. Jim Ewins was very critical of this type.

a loco boiler designed for superheaters will often 'appear' to run ok without them fitted because the free gas flow is better. but heavy coal and water consumption plus condensation in the cylinders will occur. when you have driven decent superheated locos with a good valve gear then you really notice the difference!

cheers,

julian
30 October 2015 at 00:00 #209819
duncan webster 1
Participant
@duncanwebster1
For the definative answer see **LINK**

After these tests Bill replaced the LBSC type superheaters in his loco with radiant type and then sleeved down his water pump as the loco used so much less water and therefore coal.

I accept that coaxial type don't work as well, but I don't yet see why. Transfer of heat from the hot to the cold steam can't be the answer because that would not affect the energy gained from outside the superheater system. If the hot steam flowed down the outer annulus I'd believe it lost heat by radiation to the cold flue tube (hot and cold are relative here).
30 October 2015 at 00:11 #209821
duncan webster 1
Participant
@duncanwebster1
I have a copy of Bill's later paper if anyone is interested send me a pm and I'll try to find it.
9 November 2015 at 22:21 #211356
Ron Hancock
Participant
@ronhancock63652
Hi all well struggling with another problem wondered if any one could constructively help with Info please.

I want to connect my Hair grip super heaters to the Regulator.

It has been suggested the best way is the use a Banjo Union so its fixed with a single Bolt and you can fit without having to line up 4 holes as i was going to do.

The problem i am having it can i get enough steam into through the Banjo Nut.

I need to keep it with an internal Bore of 14 can it be achieved with a single Bolt fixing and will the Bolt still be strong Enough.

Look Guys i am a Novice learning Fast but not fast enough.

Can any one really help me and point a Novice in the right direction.

The Idea seems great if i can make it work with enough steam feeding the super heaters.

The super heaters are all made in 14 with stainless tips in the fire box

Can you experienced Model Engineers point me in the right direction Please

Ron
9 November 2015 at 22:24 #211357
Ron Hancock
Participant
@ronhancock63652
Hi i forgot to add i have gone back to usig a Gas regulator with a a 10 mm Brass pipe coming from it

Ron
9 November 2015 at 22:39 #211363
julian atkins
Participant
@julianatkins58923
Hi Ron,

your concern over the 'suggestion' is very valid. i would never fit them with a banjo fitting. ive always bolted on the wet header into the regulator flange in the smokebox.

cheers,

julian
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